Copper alloy material for electrical/electronic equipments, and electrical/electronic part

ABSTRACT

A copper alloy material for an electrical/electronic equipment, containing Ni not less than 2.0 mass % and less than 3.3 mass %, having a content of Si within the range of 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, and Zn 0.2 to 1.5 mass %, with the balance of Cu and inevitable impurities, wherein when a test piece with thickness t of 0.20 mm and width w of 2.0 mm is subjected to 180°-bending with bending radius R (mm), a value of the minimum bending radius R causing no cracks is 0 mm to 0.1 mm; and, an electrical/electronic part obtained by working the same.

TECHNICAL FIELD

The present invention relates to a copper alloy material forelectrical/electronic equipments, and to an electrical/electronic part.

BACKGROUND ART

Parts of electrical/electronic equipments, for example, spring contactmaterials of connectors, are required to have properties, for example,mechanical strength, stress relaxation resistance, electricalconductivity, bending property, heat resistance, plating adhesiveness,and migration property. Conventionally, phosphor bronze has been used inmany cases, but phosphor bronze is not completely satisfactory in theproperties described above. Thus, beryllium copper, which is higher inmechanical strength and excellent in stress relaxation resistance, hasbecome used widely.

However, beryllium copper is very expensive, and metal beryllium isregarded as a substance of concern (SoC). Thus, Corson alloy(Cu—Ni—Si-based alloy), in which nickel (Ni) and silicon (Si) are addedto copper, has been attracted attention as an alloy that will substitutefor those materials.

Corson alloy is a precipitation-hardening-type alloy, which isstrengthened by dispersing and precipitating fine particles of Ni₂Siintermetallic compounds in Cu, and there have been reports on theattempts to enhance mechanical strength and electrical conductivity bydefining the amounts of addition of Ni and Si or the ratio of Ni/Si (seePatent Literatures 1 and 2). Hitherto, it is considered, in regard tothe Corson alloy, that the ratio of the contents of Ni and Si in termsof percentage by mass, that is, the value of Ni (% by mass)/Si (% bymass) (hereinafter, indicated as Ni/Si), is preferably within the rangearound 4.2, which is a stoichiometric ratio of the Ni₂Si compound thatmainly contributes to strengthening. Thus, the Ni/Si is within the rangeof Ni/Si of 3 to 7 in Patent Literature 1, and is within the range ofNi/Si of 3.5 to 5.5 in Patent Literature 2. Further, Patent Literature 1describes, with concerns about a possible lowering of the electricalconductivity caused by solid solution of Si, that in order to reduce theamount of the solid solution of Si as less as possible, the amount of Niis preferably in slight excess compared to the Ni₂Si composition, andthat Ni/Si=4.5 is most preferred. Patent Literature 2 also describesthat the Ni/Si is preferably close to 4.2, which is the stoichiometricratio of Ni₂Si, with concerns about a possible lowering of theelectrical conductivity due to an increase in the amounts of solidsolutions of Ni and Si when the value of Ni/Si is away from 4.2.

{Patent Literature 1} JP-A-2001-181759 (“JP-A” means unexaminedpublished Japanese patent application)

{Patent Literature 2} JP-A-2006-233314 DISCLOSURE OF INVENTION TechnicalProblem

However, as shown in Patent Literatures 1 and 2, the Ni/Si in theconventional alloys has been such that, while the stoichiometric ratioof Ni₂Si, or a value corresponding to an excess amount of Ni compared tothe stoichiometric ratio of Ni₂Si, is considered preferable, thedefinition of the range of the ratio is broad and ambiguous. Further,investigations have been extensively made to maintain the balancebetween mechanical strength and electrical conductivity, but sufficientinvestigations have not been made on the conditions of obtaining highmechanical strength and favorable bending property.

Thus, the present invention is contemplated for providing a copper alloymaterial for electrical/electronic equipments, having a high mechanicalstrength and a remarkably favorable bending property, and anelectrical/electronic part utilizing the same.

Solution to Problem

The inventors of the present invention have found a region to makegrains finer and to enhance aging strength, at a side of Si in excess ofthe stoichiometric ratio of Ni₂Si even in the conventional Ni/Si range.The present invention has attained based on the finding above.

According to the present invention, there is provided the followingmeans:

(1) A copper alloy material for an electrical/electronic equipment,containing Ni not less than 2.0 mass % and less than 3.3 mass %, havinga content of Si within the range of 2.8 to 3.8 in terms of a mass ratioof Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to1.5 mass %, and Zn 0.2 to 1.5 mass %, with the balance of Cu andinevitable impurities, wherein when a test piece with thickness t of0.20 mm and width w of 2.0 mm is subjected to 180°-bending with bendingradius R (mm), a value of the minimum bending radius R causing no cracksis 0 mm to 0.1 mm;(2) A copper alloy material for an electrical/electronic equipment,containing Ni not less than 2.0 mass % and less than 3.3 mass %, havinga content of Si within the range of 2.8 to 3.8 in terms of a mass ratioof Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to1.5 mass %, Zn 0.2 to 1.5 mass %, and one or more selected from thegroup consisting of Ag, Co, and Cr in a sum total of 0.005 to 2.0 mass%, with the balance of Cu and inevitable impurities, wherein when a testpiece with thickness t of 0.20 mm and width w of 2.0 mm is subjected to180°-bending with bending radius R (mm), a value of the minimum bendingradius R causing no cracks is 0 mm to 0.1 mm;(3) The copper alloy material for an electrical/electronic equipment asdescribed in item (1) or (2), which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an intermediate (cold) rolling with rolling ratioof 5 to 50%, an aging at 400 to 600° C. for 0.5 to 12 hours, a finish(cold) rolling with rolling ratio of 30% or less, and a low-temperatureannealing, in this order;(4) The copper alloy material for an electrical/electronic equipment asdescribed in item (1) or (2), which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an aging at 300 to 400° C. for 0.5 to 8 hours, afurther aging at 425 to 600° C. for 0.5 to 12 hours, a finish (cold)rolling, and a low-temperature annealing, in this order;(5) The copper alloy material for an electrical/electronic equipment asdescribed in item (1) or (2), which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an intermediate (cold) rolling with rolling ratioof 5 to 50%, an aging at 300 to 400° C. for 0.5 to 8 hours, a furtheraging at 425 to 600° C. for 0.5 to 12 hours, a finish (cold) rollingwith rolling ratio of 30% or less, and a low-temperature annealing, inthis order;(6) An electrical/electronic part obtained by working a copper alloymaterial for an electrical/electronic equipment, with the copper alloymaterial containing Ni not less than 2.0 mass % and less than 3.3 mass%, having a content of Si within the range of 2.8 to 3.8 in terms of amass ratio of Ni and Si (Ni/Si), and containing

Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, and Zn 0.2 to 1.5 mass %,with the balance of Cu and inevitable impurities, wherein when a testpiece of the copper alloy material with thickness t of 0.20 mm and widthw of 2.0 mm is subjected to 180°-bending with bending radius R (mm), avalue of the minimum bending radius R causing no cracks is 0 mm to 0.1mm; and

(7) An electrical/electronic part obtained by working a copper alloymaterial for an electrical/electronic equipment, with the copper alloymaterial containing Ni not less than 2.0 mass % and less than 3.3 mass%, having a content of Si within the range of 2.8 to 3.8 in terms of amass ratio of Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %,Sn 0.05 to 1.5 mass %, Zn 0.2 to 1.5 mass %, and one or more selectedfrom the group consisting of Ag, Co, and Cr in a sum total of 0.005 to2.0 mass %, with the balance of Cu and inevitable impurities, whereinwhen a test piece of the copper alloy material with thickness t of 0.20mm and width w of 2.0 mm is subjected to 180°-bending with bendingradius R (mm), a value of the minimum bending radius R causing no cracksis 0 mm to 0.1 mm.

ADVANTAGEOUS EFFECTS OF INVENTION

The copper alloy material of the present invention forelectrical/electronic equipments has a higher electrical conductivitythan conventional phosphor bronze, has an electrical conductivity at thesame level as or higher than beryllium copper (C17200, C17530), and thushas a sufficient electrical conductivity for the use in connectors. Thecopper alloy material also has a high mechanical strength and has aremarkably favorable bending property. Further, since theelectrical/electronic part of the present invention is obtained byworking the copper alloy material for electrical/electronic equipments,the part has a high mechanical strength and also has a remarkablyfavorable bending property required for parts of the connector use.

Other and further features and advantages of the invention will appearmore fully from the following description.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, by setting the content of Ni to not less than2.0 mass % and less than 3.3 mass %, the resultant copper alloy materialcan have a sufficient electrical conductivity, a high mechanicalstrength, and a remarkably favorable bending property. When the contentof Ni is less than the lower limit value, a sufficient strength cannotbe obtained. Further, when the content of Ni exceeds the upper limitvalue, the thus-obtained copper alloy material has a high strength buttends to have a low electrical conductivity.

Further, in the present invention, the Ni/Si (mass ratio of thecontents) is defined to be within the range of 2.8 to 3.8. By settingthe ratio within this range, since precipitation of Ni₃Si₂ can beexpected in addition to the precipitation of Ni₂Si and the precipitationdensities of Ni₂Si and Ni₃Si₂ are increased, the tensile strength isenhanced upon aging. Further, since the grain size upon the solutiontreatment can be controlled to be smaller as a result of an increase inthe amount of solid solution of Si, the grains also act satisfactorilyin the bending property. When the ratio is greater than the upper limitvalue, the required effect of enhancing the strength upon the agingcannot be obtained. On the other hand, when the ratio is less than thelower limit value, the required effect of enhancing the strength uponthe aging cannot be obtained, and the electrical conductivity is loweredby the amount of solid solution of Si is more noticeable than the effectof controlling the grain size, which exerts an adverse influence. A morepreferable range of the Ni/Si is around 3.3, which is 3.0 to 3.5. Whenthe ratio is in this range, a material can be obtained which isfavorable in the balanced of the tensile strength, the electricalconductivity, and the bending property.

Mg improves the stress relaxation resistance, but its content is definedto 0.01 to 0.2 mass %, since when the content is less than 0.01 mass %,an improvement in the stress relaxation resistance cannot be seen, andwhen the content is greater than 0.2 mass %, Mg in such a too highcontent gives adverse affects on the bending property. The content of Mgis preferably 0.05 to 0.15 mass %.

Sn is interrelated with Mg, thereby to improve the stress relaxationresistance further. The content of Sn is defined to 0.05 to 1.5 mass %,because when the content is less than 0.05 mass %, the effects are notsufficiently obtained, and when the content is greater than 1.5 mass %,the electrical conductivity is lowered. The content of Sn is preferably0.1 to 0.7 mass %.

Zn slightly improves the bending property. Preferably, when the amountof Zn is defined to 0.2 to 1.5 mass %, the bending property can beobtained at a level that is free of problem for practical use even if Mgis added in an amount up to 0.2 mass % at the maximum. In addition tothat, Zn improves the adhesiveness of Sn plating or solder plating, orthe migration property. When the amount of Zn is greater than 1.5 mass%, the electrical conductivity is lowered. The content of Zn is morepreferably 0.3 to 1.0 mass %.

The copper alloy material of the present invention may also contain oneor two or more of Ag, Co, and Cr in 0.005 to 2.0 mass % in a total ofthose, in addition to the elements described above.

Ag improves the heat resistance and enhances the strength, and alsoinhibits coarsening of the grains, thereby to improve the bendingproperty.

When the amount of Ag is less than 0.005 mass %, the effects are notsufficiently obtained, and even if Ag is added in an amount greater than0.3 mass %, the production cost increases without any adverse affects onthe properties. From those points of view, the content of Ag is definedto 0.005 to 0.3 mass %.

Similarly to Ni, Co forms a compound with Si, to enhance the strength.When the content of Co is less than 0.05 mass %, the effects are notsufficiently obtained, and when the content is greater than 2.0 mass %,crystallization and precipitation products which do not contribute tothe strength are present even after the solution treatment, so that thebending property is deteriorated.

Cr precipitates as a second phase with Ni and/or Si, and is effective inthe control of the grain size. When the content is less than 0.05 mass%, the effects are not sufficiently obtained, and when the content isgreater than 1.0 mass %, the bending property is deteriorated.

In the case of adding two or more of Ag, Co, and Cr, the contents aredetermined within the range of 0.005 to 2.0 mass %, according to therequired properties.

The copper alloy material for electrical/electronic equipments of thepresent invention is preferably produced by the steps of: casting, hotrolling, dough rolling, and solution treatment, followed by intermediaterolling, aging, finish rolling, and low-temperature annealing.

The shape of the copper alloy material for electrical/electronicequipments of the present invention is not particularly limited, andexamples include sheet (plate), strip, wire, rod, and foil.

A preferred method of producing the copper alloy material of the presentinvention is explained in detail below. In the following, a method ofproducing a copper alloy sheet or a copper alloy strip is described indetail as a representative example.

In the present invention, the casting is conducted by a usual DC (directchill casting) method, or the like. It is preferable that, immediatelyafter conducting a homogenization treatment of the resultant ingot at atemperature of 850° C. to 1,000²C for 0.5 to 12 hours, the hot rollingis conducted at a temperature of 700° C. to 950²C, followed by watercooling to prevent precipitation in the cooling. After the hot rolling,an oxide layer is face-milled, followed by the cold rolling.Hereinafter, this cold rolling is referred to as dough rolling. Thedough rolling is conducted to a sheet thickness, to give a given workingratio in the intermediate rolling and the finish rolling, respectively.

It is preferable that the solution treatment is conducted at amaterial's substantial temperature of 700° C. to 880° C., followed bymaintaining for approximately 3 to 6 seconds, and cooling with a coolingspeed of 15° C./sec or more (more preferably 30° C./sec or more) toprevent precipitation. When the solution treatment temperature is lowerthan 700° C., such problems occur that it is not possible to obtain asound recrystallized structure, to affect as negatively to the bendingproperty, and that the amounts of the solid solution of Ni and Si becomeinsufficient, to result in an insufficient precipitated amount of theNi—Si-based precipitation upon the aging, thereby to fail to obtain asufficient proof stress. When the solution treatment temperature ishigher than 880° C., coarsening of the recrystallized grains occur, tocause lowering of the strength, exhibition of an anisotropy, anddeterioration of the bending property.

As the intermediate rolling, a cold-rolling is conducted, to enhance thetensile strength and the proof stress upon the aging. Dislocations areintroduced into the matrix of the copper alloy upon the intermediaterolling, but a part of the dislocations function as the heterogeneousnucleation sites of the Ni—Si-based compound in the subsequent agingstep, aiding the formation of the compound at a high density with a finesize, and enhancing further the effect of increasing the precipitationdensity owing to the controlling of the Ni/Si. It is preferable tointroduce the intermediate rolling, to enhance the aging strength aswell; but if the rolling ratio is too high, the effect of enhancing theaging strength is saturated and the bending property is deteriorated.Thus, it is preferable to conduct the intermediate rolling within therange of rolling ratio 5 to 50%.

The aging makes it possible to precipitate and disperse the Ni₂Si andNi₃Si₂ compounds uniformly into the copper matrix, to enhance thestrength and improve the electrical conductivity. It is preferable toconduct the aging with a batch-type furnace, to maintain at a material'ssubstantial temperature of 400° C. to 600° C. for 0.5 to 12 hours. Whenthe substantial temperature is lower than 400° C., a quite longer periodof time is necessary to obtain a sufficient precipitation amount of theNi—Si-based compound, or the proof stress and the electricalconductivity result in insufficient. When the substantial temperature ishigher than 600° C., the Ni—Si-based compound becomes coarsened, to failto obtain the proof stress sufficiently.

Furthermore, when the aging is carried out in two stages of: aging at asubstantial temperature of the material of 300 to 400° C. for 0.5 to 8hours, and then aging at a substantial temperature of 425 to 600° C. for0.5 to 12 hours, it is possible to increase the precipitation density ofthe Ni—Si-based compound and to further enhance the strength and improvethe bending property. When this two-stage aging is carried out, theintermediate rolling may not be carried out; but by conducting theintermediate rolling, the strength can be further enhanced.

As the finish rolling, a cold-rolling is conducted to enhance the proofstress. When the proof stress after the aging is sufficient, it may bepossible to omit the finish rolling and the subsequent low-temperatureannealing. When the rolling ratio in the finish rolling is too high, thebending property is deteriorated and the stress relaxation resistance isdeteriorated. Thus, the finish rolling is preferably conducted with arolling ratio of 30% or less.

The low-temperature annealing is conducted to recover an elongation, thebending property, and a spring limit value, while maintaining thestrength in a certain degree. When the substantial temperature at thelow-temperature annealing is too high, recrystallization occurs, tocause lowering of the proof stress. Thus, it is preferable to conductthe annealing at the substantial temperature of 300 to 600° C. for ashort period of time of 5 to 60 seconds. When the substantialtemperature is lower than 300° C., the recovery of the elongation, thebending property, and the spring limit value becomes insufficient. Whenthe substantial temperature is higher than 600° C., it results inlowering of the strength.

Further, the electrical/electronic part of the present invention can beobtained by appropriately working the copper alloy material forelectrical/electronic equipments. This working method is notparticularly limited, and the part may be fabricated into a desired partshape in a usual manner, for example, by plastic working, such as pressworking.

EXAMPLES

The present invention will be described in more detail based on examplesgiven below, but the invention is not meant to be limited by these.

Example 1

Copper alloys having compositions shown in Table 1, were melt, followedby casting into ingots with thickness 30 mm, width 100 mm, and length150 mm, by the DC method, respectively. Then, the ingots were heated to900° C., to maintain at this temperature for 1 hour, followed by hotrolling to thickness 12 mm, and cooling immediately thereafter. Then,the oxide film layer was removed by face-milling the respective face in1.5 mm for each, followed by dough rolling to thickness 0.25 to 0.50 mm.Then, the resultant sheets were subjected to a solution treatment underany of conditions at 750° C. to 880° C., followed, immediatelythereafter, by cooling with a cooling speed of 15° C./sec or more. Then,the resultant sheets were subjected to intermediate rolling with rollingratio 5 to 50%. Then, the resultant sheets were subjected to aging at450 to 550° C. for 2 hours in an inert gas atmosphere, followed byfinish rolling with rolling ratio 30% or less, to adjust the final sheetthickness to 0.20 mm. After the finish rolling, the sheets weresubjected to a low-temperature annealing at 500° C. for 30 seconds, andthe thus-obtained materials were utilized to conduct the followingvarious property evaluations. Herein, the unit for elements of thecopper alloy (Ni, Si, and the like) indicated in the respective table isall percentage by mass (mass %), except for the value of Ni/Si (no unit)which is in terms of mass ratio.

Then, with respect to the copper alloy sheets produced in the above,investigation was carried out on (1) grain size, (2) tensile strength,(3) electrical conductivity, and (4) bending property. The results areshown in Table 1.

(1) The grain size was measured, according to JIS H 0501 (the cuttingmethod).(2) The tensile strength was measured with a No. 5 test piece asspecified in JIS Z 2201, according to JIS Z 2241. The tensile strengthwas indicated as a value rounded off to an integer multiple of 5 MPa.(3) The electrical conductivity was measured, according to JIS H 0505.(4) The bending property was defined as R/t, which was a ratio of theminimum bending radius (R) at which no cracks occurred and the sheetthickness (t), with a bending test piece with width w of 2 mm and sheetthickness t of 0.20 mm, in a 180°-bending test conducted with bendingradius R (mm) of 0 to 0.6. When cracks occurred even at R/t of 3.0, theresult was indicated as R/t>3. The evaluation of the bent portion wascarried out, according to the Japan Brass Makers Association, TechnicalStandard, “Evaluation on Bending Property of Thin Sheet and Strip ofCopper and Copper Alloys” (JBMA T307:1999).

TABLE 1 Tensile Electrical Bending Elements Grain size strengthconductivity property No. Ni Si Zn Mg Sn Others Ni/Si mm MPa % IACS R/tExample of 1 2.03 0.66 0.52 0.11 0.16 3.1 0.006 750 41 0 this invention2 2.31 0.80 0.51 0.11 0.15 2.9 0.005 765 35 0 3 2.30 0.61 0.51 0.11 0.153.8 0.008 765 39 0 4 2.31 0.66 0.51 0.11 0.15 3.5 0.006 770 38 0 5 2.290.65 0.51 0.11 0.15 0.03 Ag 3.5 0.006 775 38 0 6 2.31 0.68 0.51 0.110.15 0.05 Co 3.4 0.006 775 38 0 7 2.31 0.67 0.51 0.11 0.15 0.1 Cr, 0.03Ag 3.4 0.005 780 37 0 8 2.30 0.70 0.51 0.11 0.15 0.2 Cr 3.3 0.005 785 370 9 3.22 0.95 0.51 0.11 0.15 3.4 0.006 840 35 0.5 10 3.21 0.95 0.51 0.110.15 0.1 Cr 3.4 0.005 855 35 0.5 Comparative 11 1.70 0.53 0.53 0.11 0.153.2 0.008 640 41 0 example 12 1.91 0.60 0.51 0.10 0.15 3.2 0.008 690 400 13 2.03 0.47 0.52 0.11 0.16 4.3 0.015 710 42 1 14 2.03 0.80 0.52 0.110.16 2.5 0.005 700 30 0 15 2.30 0.50 0.54 0.10 0.15 4.6 0.016 730 42 116 2.29 0.51 0.54 0.10 0.15 0.03 Ag 4.5 0.014 735 41 1 17 2.33 0.50 0.540.10 0.15 0.05 Co 4.7 0.014 735 41 1 18 2.31 0.50 0.54 0.10 0.15 0.1 Cr4.6 0.013 740 41 1 19 2.30 0.51 0.54 0.10 0.15 0.1 Cr, 0.03 Ag 4.5 0.013740 41 1 20 2.34 0.60 0.52 0.11 0.15 3.9 0.013 740 40 0.5 21 2.33 0.850.50 0.10 0.15 2.7 0.005 730 32 0 22 2.31 1.00 0.54 0.10 0.15 2.3 0.004720 30 0.5 23 3.20 0.70 0.51 0.09 0.15 4.6 0.015 805 36 2 24 3.20 1.200.51 0.09 0.15 2.7 0.005 795 29 1 Reference 25 3.40 1.04 0.50 0.10 0.163.3 0.006 805 33 1 example 26 3.60 1.10 0.51 0.09 0.15 3.3 0.006 850 32>3

As shown in Table 1, Examples 1 to 10 according to the present inventionexhibited excellent characteristics in both of a high tensile strengthand an excellent bending property. Examples 1 to 10 according to thepresent invention each had an electrical conductivity of 35% IACS orhigher, a tensile strength of 750 MPa or higher, and the bendingproperty in the value of R/t of 0 to 0.5.

Comparative examples 11 and 12 had the Ni/Si within the defined range,but since the amount of Ni was less than the lower limit value, thestrength was insufficient. Comparative examples 13, 15 to 20, and 23,which had the ratios Ni/Si greater than the upper limit value, werelower in the mechanical strength, as compared with those of the examplesaccording to the present invention having the correspondingcompositions, respectively. Furthermore, since these comparativeexamples were large in the grain size, they were poor in the bendingproperty. Comparative examples 14, 21, 22, and 24, which had the ratiosNi/Si less than the lower limit value, were lower in the mechanicalstrength, as compared with those of the examples according to thepresent invention having the corresponding compositions, respectively,and furthermore these comparative examples were also poor in theelectrical conductivity. Comparative example 24 was also poor in thebending property. Reference examples 25 and 26 had larger amounts of Nicompared to the defined range, and thus they failed to obtain such theremarkably favorable bending property as in the examples according tothe present invention.

Example 2

Using the ingots of Nos. 4, 15, and 22, as produced in the above Example1, the results are shown in Table 2, in which investigations were madeon the effects of changing the post-solution treatment steps. Thenumbers shown in Table 2 are indicated such that, for example, when theproduction process was modified using the ingot No. 4, the instance isindicated with a sub-number such as 4-2.

Example 4-2 according to the present invention, and Comparative examples15-2 and 22-2 were produced, in the same production process as describedin the above Example 1, except for changing the aging to a two-stageaging treatment to conduct aging at 350° C. for 2 hours and then agingat 500° C. for 2 hours. Example 4-3 according to the present invention,and Comparative examples 15-3 and 22-3 were produced, in the sameproduction process as described in the above Example 1, except for notconducting the intermediate rolling immediately before the agingtreatment, and changing the aging to a two-stage aging treatment toconduct aging at 350° C. for 2 hours and then aging at 500° C. for 2hours. Reference example 4-4 was a test example in which the sameproduction process as described in the above Example 1 was carried out,except for not conducting the intermediate rolling immediately beforethe aging treatment, and changing the aging to a single stage agingtreatment at 500° C. for 2 hours, which is a comparative example withrespect to the invention according to the item (3) above.

The investigation on the properties was carried out, with respect to thecopper alloy sheets, in the same manner as in the above Example 1, on(1) grain size, (2) tensile strength, (3) electrical conductivity, and(4) bending property. The results are shown in Table 2.

TABLE 2 Tensile Electrical Bending Elements Grain size strengthconductivity property No. Ni Si Zn Mg Sn Others Ni/Si mm MPa % IACS R/tExample of  4-2 2.31 0.66 0.51 0.11 0.15 3.5 0.006 835 41 0 thisinvention  4-3 2.31 0.66 0.51 0.11 0.15 3.5 0.006 805 40 0 Reference 4-4 2.31 0.66 0.51 0.11 0.15 3.5 0.008 770 36 >3 example Comparative15-2 2.30 0.50 0.54 0.10 0.15 4.6 0.016 770 41 1 example 15-3 2.30 0.500.54 0.10 0.15 4.6 0.016 750 41 1 22-2 2.31 1.00 0.54 0.10 0.15 2.30.004 765 31 0.5 22-3 2.31 1.00 0.54 0.10 0.15 2.3 0.004 750 31 0.5

Examples 4-2 and 4-3 according to the present invention each hadachieved a higher mechanical strength than Example No. 4 according tothe present invention of the above Example 1, and an excellent bendingproperty.

Contrary to the above, Comparative examples 15-2 and 15-3, which had theNi/Si larger than the upper limit value, were lower in the mechanicalstrength with no effects of modifying the process, as compared toExamples 4-2 and 4-3 according to the present invention; and since theywere larger in the grain size, they were poor in the bending property.Comparative examples 22-2 and 22-3, which had the Ni/Si less than thelower limit value, were low in the electrical conductivity, and low inthe mechanical strength, as compared to Examples 4-2 and 4-3 accordingto the present invention with no effects of modifying the process.Further, Reference example 4-4, which was a test example in which thefinish rolling ratio was increased so as to try to enhance themechanical strength, but the resultant strength was rather lowered, andthe bending property was poor.

INDUSTRIAL APPLICABILITY

The copper alloy material for electrical/electronic equipments of thepresent invention has a high mechanical strength and is excellent in thebending property, and thus can be favorably used in parts forelectrical/electronic equipments, particularly in spring contacts ofconnectors, and the like. Furthermore, since the electrical/electronicpart of the present invention is one obtained by working the copperalloy material for electrical/electronic equipments, the part isfavorable as a part for the use in connectors, where a remarkablyfavorable bending property is required, despite of having a highmechanical strength.

Having described our invention as related to the present embodiments, itis our intention that the invention not be limited by any of the detailsof the description, unless otherwise specified, but rather be construedbroadly within its spirit and scope as set out in the accompanyingclaims.

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2008-092314 filed in Japan on Mar. 31,2008, which is entirely herein incorporated by reference.

1. A copper alloy material for an electrical/electronic equipment,containing Ni not less than 2.0 mass % and less than 3.3 mass %, havinga content of Si within the range of 2.8 to 3.8 in terms of a mass ratioof Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to1.5 mass %, and Zn 0.2 to 1.5 mass %, with the balance of Cu andinevitable impurities, wherein when a test piece with thickness t of0.20 mm and width w of 2.0 mm is subjected to 180°-bending with bendingradius R (mm), a value of the minimum bending radius R causing no cracksis 0 mm to 0.1 mm.
 2. The copper alloy material for anelectrical/electronic equipment according to claim 1, which is producedby subjecting a cast ingot to a hot rolling, a dough (cold) rolling, anda solution treatment, followed by an intermediate (cold) rolling withrolling ratio of 5 to 50%, an aging at 400 to 600° C. for 0.5 to 12hours, a finish (cold) rolling with rolling ratio of 30% or less, and alow-temperature annealing, in this order.
 3. The copper alloy materialfor an electrical/electronic equipment according to claim 1, which isproduced by subjecting a cast ingot to a hot rolling, a dough (cold)rolling, and a solution treatment, followed by an aging at 300 to 400°C. for 0.5 to 8 hours, a further aging at 425 to 600° C. for 0.5 to 12hours, a finish (cold) rolling, and a low-temperature annealing, in thisorder.
 4. The copper alloy material for an electrical/electronicequipment according to claim 1, which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an intermediate (cold) rolling with rolling ratioof 5 to 50%, an aging at 300 to 400° C. for 0.5 to 8 hours, a furtheraging at 425 to 600° C. for 0.5 to 12 hours, a finish (cold) rollingwith rolling ratio of 30% or less, and a low-temperature annealing, inthis order.
 5. A copper alloy material for an electrical/electronicequipment, containing Ni not less than 2.0 mass % and less than 3.3 mass%, having a content of Si within the range of 2.8 to 3.8 in terms of amass ratio of Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %,Sn 0.05 to 1.5 mass %, Zn 0.2 to 1.5 mass %, and one or more selectedfrom the group consisting of Ag, Co, and Cr in a sum total of 0.005 to2.0 mass %, with the balance of Cu and inevitable impurities, whereinwhen a test piece with thickness t of 0.20 mm and width w of 2.0 mm issubjected to 180°-bending with bending radius R (mm), a value of theminimum bending radius R causing no cracks is 0 mm to 0.1 mm.
 6. Thecopper alloy material for an electrical/electronic equipment accordingto claim 5, which is produced by subjecting a cast ingot to a hotrolling, a dough (cold) rolling, and a solution treatment, followed byan intermediate (cold) rolling with rolling ratio of 5 to 50%, an agingat 400 to 600° C. for 0.5 to 12 hours, a finish (cold) rolling withrolling ratio of 30% or less, and a low-temperature annealing, in thisorder.
 7. The copper alloy material for an electrical/electronicequipment according to claim 5, which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an aging at 300 to 400° C. for 0.5 to 8 hours, afurther aging at 425 to 600° C. for 0.5 to 12 hours, a finish (cold)rolling, and a low-temperature annealing, in this order.
 8. The copperalloy material for an electrical/electronic equipment according to claim5, which is produced by subjecting a cast ingot to a hot rolling, adough (cold) rolling, and a solution treatment, followed by anintermediate (cold) rolling with rolling ratio of 5 to 50%, an aging at300 to 400° C. for 0.5 to 8 hours, a further aging at 425 to 600° C. for0.5 to 12 hours, a finish (cold) rolling with rolling ratio of 30% orless, and a low-temperature annealing, in this order.
 9. Anelectrical/electronic part obtained by working a copper alloy materialfor an electrical/electronic equipment, with the copper alloy materialcontaining Ni not less than 2.0 mass % and less than 3.3 mass %, havinga content of Si within the range of 2.8 to 3.8 in terms of a mass ratioof Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to1.5 mass %, and Zn 0.2 to 1.5 mass %, with the balance of Cu andinevitable impurities, wherein when a test piece of the copper alloymaterial with thickness t of 0.20 mm and width w of 2.0 mm is subjectedto 180°-bending with bending radius R (mm), a value of the minimumbending radius R causing no cracks is 0 mm to 0.1 mm.
 10. Anelectrical/electronic part obtained by working a copper alloy materialfor an electrical/electronic equipment, with the copper alloy materialcontaining Ni not less than 2.0 mass % and less than 3.3 mass %, havinga content of Si within the range of 2.8 to 3.8 in terms of a mass ratioof Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to1.5 mass %, Zn 0.2 to 1.5 mass %, and one or more selected from thegroup consisting of Ag, Co, and Cr in a sum total of 0.005 to 2.0 mass%, with the balance of Cu and inevitable impurities, wherein when a testpiece of the copper alloy material with thickness t of 0.20 mm and widthw of 2.0 mm is subjected to 180°-bending with bending radius R (mm), avalue of the minimum bending radius R causing no cracks is 0 mm to 0.1mm.